Sirenia

Definitions

from Wiktionary, Creative Commons Attribution/Share-Alike License

proper n. A taxonomic order within the subclass Placentalia — the sirenians.

from the GNU version of the Collaborative International Dictionary of English

n.pl. An order of large aquatic herbivorous mammals, including the manatee, dugong, rytina, and several fossil genera.

from The Century Dictionary and Cyclopedia

n. The sirenian mammals or so-called herbivorous cetaceans, an order of educabilian placental Mammalia, having the body fish-like in form, with the hind limbs and pelvis more or less completely atrophied, and the body ending in a horizontal expansive tail, either rounded or like the flukes of a cetacean.

The language used by the characters was rather different than usual, pleasantly old fashioned I guess and unexpected since the dialogue is usually more casual/modern in Sirenia stories (not that it's always the same, like the recentish Eighth Veil which I also loved) ...

I think I'll be taking replies most of the month, and the best will be included in Sirenia Digest #50 (printed anonymously, and the responses are being screened, so I'm the only person who will see your reply to the post with your screen name attached).